Allow heat-admin to sudo without tty

This is needed to run scripts from devtest, in particular so that
swift ring files can be distributed.

Change-Id: Icbe8c5b24a0d494730357983f230a37a7f078de7
Add mapping for libffi-dev

libffi header files are needed to pip install xattr, which is a
requirement of swift.

Change-Id: I69560425f7106c35ec432825eab94ca8424eb89e
Merge "Allow heat-admin to sudo without tty"
Merge "Add mapping for libffi-dev"